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Hey guys,I think I'm about to start collecting parts to build a few hydraulic things I've been thinking of. Mostly a decent press, and maybe the enerpac maintenance set.. Been looking at all the different types of pumps, and I had a question about the double action manual pumps..Can I use a double acting manual pump with a work holding valve on a single acting cylinder?Can I plug port B permanently (for the time being), open the work holding valve while pumping, then close it to lock the system. If I need to release the pressure slowly, can I put the double acting pump in neutral, then slowly open the valve to release pressure? And just keep port B closed, and only use the 3 way valve in position 1 (pressure to port A, return to B (blocked)) and in position 2 (both in 'neutral').. with the addition of the valve? That way if I ever need to run a double acting cylinder, I don't have to upgrade anything..Any ideas?Miller: 200dx, Bobcat 225, Passport, Powermax 45, Milwaukee: Dry Saw, MagDrill, grinders
Reply:Take this bit of information for what it is...wild *** guess/BS. I wouldn't permanently plug the 'B' side of the pump, but instead use it for releasing the pressure from the cylinder back into the pump body. You may still have a problem waiting to happen if the volume of the 'B' side is less than the oil residing in the cylinder. If that happens (not sure it will) you can also plumb the release into the oil fill opening of the pump with a T-connection with one leg of the T having a breather orifice (hopefully screened) to allow excess air pressure to escape (and again...hopefully...let the cylinder's oil pass into the pump and not out the breather orifice). A simpler method would probably be a direct T-connection between the cylinder and the 'A' side pressure outlet upstream from your holding valve with a breather orifice installed on the pump's regular oil fill location (possibly plumbed in and extended upwards to minimize the possibility of oil from the return seeking free access outward through the breather orifice.)I did a conversion on a motorized hydraulic power head for use on a one-way cylinder application this way (breather installed). Still, lot of difference between the single acting cylinder and double acting. Also, the breather (plug in this case, installed in the hyd. power head's oil fill location) was not connected to the return line between the cylinder and the pump and sat at the highest part of the hyd. power head.Hope you get better advice from others before attempting this project.Best of luck and report back.Lincoln PrecisionTig 275Miller 251Miller DialArc 250Bridgeport millHossfeld bender & diesLogan shaperJet 14 X 40 latheSouth Bend 9" 'C'Hypertherm 900Ellis 3000 band saw21"Royersford ExcelsiorTwo shops, still too many tools. |
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